Year	Percent
1991	25.491
1992	26.045
1993	26.547
1994	27.675
1995	27.439
1996	28.208
1997	28.859
1998	28.538
1999	27.721
2000	28.1
2001	26.897
2002	26.867
2003	26.485
2004	27.979
2005	29.711
2006	30.449
2007	30.534
2008	30.869
2009	29.209
2010	30.413
2011	31.16
2012	30.804
2013	31.248
2014	32.523
2015	32.144
2016	31.696
2017	31.648
2018	31.824
2019	31.95
2020	32.073
2021	32.177
2022	32.271